Representative LD50 Values
Toxin or venom (source)
Water (various)
Ethanol (fermentation of sugars)
NaCl (prepared food)
Mouse
LD50
(mg/kg)
2 x 10
5
104
4 x 103
Mechanism
CNS depression; cerebral edema; brain herniation.
GABA receptor agonist  CNS inhibition.
Excitable cell membrane electrical effects; osmotic disruption of cells
Morphine sulfate (Papaver somniferum)
900
Endorphin receptor agonist  CNS inhibition.
Potassium chloride (geologic)
350
Excitable cell membrane electrical effects  nervous system
disruption, cardiac arrhythmia
Salycilates (Salix spp.)
250
Uncouples oxidative phosphorylation
Strychnine sulfate (Strychnos nux vomica)
150
CNS de-inhibition
Plutonium (geologic)
80
Ionizing radiation effects in lungs, intestines
Thiopental (synthetic)
50-70
CNS inhibition; respiratory failure
Arsenic trioxide (geologic)
20
Binds sulfhydryl groups in proteins; ‘replaces’ PO4 in ADP + PO4 
ATP (get ADP-arsenate, instead)
Hydrogen cyanide (many plant species)
3.7
Blocks final step of electron transport chain.
Rattlesnake venom – cytotoxic (Crotalus spp.)
2-6
Enzymatic destruction of plasma membranes
Batrachotoxin (Choresine spp.)
2.0
Prolonged opening of Na+ channels  nervous system inhibition 
respiratory paralysis
T2 Toxin (Fusarium spp.)
1.2
Disrupts protein synthesis at several stages of translation
Nicotine (Nicotiana spp.)
1
Latrotoxin (Latrodectus mactans)
0.55
Curare (Chondrodendron tomentosum)
0.5
Kallikrein, natriuretic-type toxin (Varanus
komodoensis)
Rattlesnake venom – neurotoxic (Crotalus spp.)
 0.4
0.2-0.7
Aconitine (Aconitum heterophyllum)
0.1
Sarin (synthetic)
0.1
-bungarotoxin (Bungarus multicinctus)
0.08
Soman, or GD (synthetic)
0.06
Anatoxin (Anabena flos-aquae)
0.05
Microcystin (Microcystis aeruginosa)
0.05
Enterotoxin B (Staphylococcus aureus)
0.027
VX (synthetic)
0.015
Saxitoxin (Alexandrium spp.)
0.01
Non-competitive agonist/antagonist of nACh receptor  excitation of
nervous system, followed by paralysis, respiratory failure
Hyperactivation of muscles of body
Competitive inhibitor of nACh receptor  paralysis, respiratory
failure
Peripheral vasodilation,  vascular permeability  profound
hypotension, circulatory collapse
Non-competitive inhibitor of nACh receptor  paralysis, respiratory
failure
Na+ channel blocker  cardiac arrhythmia
Noncompetitive inhibitor of myoneural junction AChase  severe
seizures that can result in death
Non-competitive inhibitor of nACh receptor  weakness, paralysis,
respiratory failure
Noncompetitive inhibitor of myoneural junction AChase  severe
seizures that can result in death
Non-competitive agonist of nACh receptor  excitation of nervous
system, seizures (BTW, “Ana” is from Anas, a genus of ducks)
Hepatotoxic due to apotosis of hepatocytes subsequent to disrupted
protein dynamics.
‘Hyperactivation’ of T-cells  cytokine ‘storm’  pulmonary
edema, circulatory collapse
Noncompetitive inhibitor of myoneural junction AChase  severe
seizures that can result in death
Nervous system Na+ channel blocker  paralysis, respiratory failure
-Tityustoxin (Tityus spp.)
0.009
Unnamed -neurotoxin (Oxyuranus scutellatus)
0.009
Tetrodotoxin (Vibrio spp..)
0.008
-conotoxin (Conus spp.)
0.005
Taipoxin (Oxyuranus suctellatus)
0.005
Ricin (Rincus communis)
0.003
CP Enterotoxin (Clostridium perfringens)
0.003
Unnamed -toxin (Oxyuranus microlepidotus)
 0.002
CNS K+ channel blocker  severe hypertension, pulmonary edema,
cor pulmonae.
Non-competitive inhibitor of nACh receptor  paralysis, respiratory
failure
Nervous system Na+ channel blocker  paralysis, respiratory failure
Competitive inhibitor of nACh receptor  paralysis, respiratory
failure
Rhabdomyolysis; disrupted release of neurotransmitters by CNS
neurons  paralysis, respiratory failure
Enzymatic degradation of rRNA  blockage of protein synthesis
Pore-forming proteins  dramatically  plasma membrane
permeability  apoptosis
Non-competitive inhibitor of nACh receptor  paralysis, respiratory
failure
Locks voltage-gated Na+ channels in open conformation  disrupted
neural function, cardiac arrhythmias
Causes death of endothelial cells in GI & renal capillaries 
bleeding, renal failure
gene expression – many genes, many cell types  malignant
transformation, apoptosis
Blocks release of ACh at neuromuscular junction  paralysis,
respiratory failure
Locks voltage-gated Na+ channels in open conformation  disrupted
neural function, cardiac arrhythmias
Converts Na+K+-ATPase into an ion channel  disrupted
transmembrane ion fluxes; cell death due to Ca++ overloading
Disrupts function of ribosomal elongation factor 1  blockage of
protein synthesis
Ca++ channel activator   release of norepinephrine by numerous
tissues  adrenergic storm
Batrachotoxin (Choresine spp.)
0.002
Verotoxin (Escherichia coli Strain O157:H7)
0.002
Dioxin (synthetic)
0.001
Textilotoxin (Pseudonaja textilis)
0.0006
Ciguatoxin (Gambierdiscus toxicus)
0.0004
Palytoxin (various marine species)
0.00015
Diphtheria toxin (Corynebacterium diphtheriae)
0.0001
Maitotoxin (Gambierdiscus toxicus)
0.0001
Abrin (Abrus precatorius)
0.00004
Enzymatic degradation of rRNA  blockage of protein synthesis
Shiga Toxin (Shigella dysenteriae)
0.000002
Enzymatic degradation of rRNA  blockage of protein synthesis
Tetanus Toxin (Clostridium tetani)
0.000002
Botulinum toxin (Clostridium botulinum)
0.000001
Enzymatic destruction of SNARE complex in glycine-dependent
synapses  seizures
Enzymatic destruction of SNARE complex in ACh-dependent
synapses  weakness, paralysis, respiratory failure